Facebook's user growth has remained remarkably steady over time.
Graph by Ben Parr/CNET

Many people believe Facebook's growth is slowing down, but the raw numbers seem to tell a different story.

The world's largest social network recently celebrated a major milestone: 1 billion monthly active users. It took the company eight years -- or more specifically 105 months -- to reach the historic mark.

The milestone made me curious: is Facebook's growth stalling, or does it still have some fight in it left? Could Facebook reach 1.1 billion users early next year? What about 1.5 billion users in four? Two billion users in eight?

In order to better understand Facebook's user growth, I decided to analyze the numbers and graph out the company's user count from its launch in February 2004 to today.

It took 55 months for Facebook to reach 100 million users, but it only took eight months for the social network to reach 200 million. Even more insane: Facebook reached 300 million users just five months later.

After that, the growth is remarkably consistent. It took five months for Facebook to go from 300 million to 400 million users, from 400 million to 500 million users, and from 500 million to 600 million users. In contrast, it took seven months for Facebook to go from 800 million to 900 million users, and it took six months to go from 900 million users to 1 billion.

I was honestly shocked by the numbers. I thought Facebook's growth was rapidly decelerating, when in reality it's still adding nearly 200 million active users every year or so. If one were to take a conservative stance and say that it will take Facebook another seven months to add another 100 million users, then Facebook is still going to be celebrating 1.2 billion users by the end of 2013. That's incredibly impressive.

Of course, Facebook's growth has to slow down at some point. There are only so many people in the world that have access to the Internet. But it seems clear that the world's largest social network still has plenty of room to become even bigger.